1. Field of the Invention
This invention relates to a optical fiber guided projectile system, and, more particularly, to an optical fiber guided projectile capable of being fired from a tubular launcher, such as a mortar or a cannon, and to the control system therefor.
2. Description of Related Art
Means for in-flight guidance of projectiles, such as missiles, are known. Originally, such guidance was primarily provided through means of on-board systems. The complexity and cost of these systems led to radio, radar or laser controlled systems. These systems also required expensive and complex equipment to be carried by the projectile and were subject to interference with the signals to or from the projectile. A more recent development is the wire guided projectile. Such systems eliminated the need for complex on-board equipment and precluded interference with data transfer. These systems, however, were limited in terms of the volume and direction of data transfer to and from the projectile.
The advent of optical fiber as a communication means offers advantages over the wire guided systems since optical fibers can transmit substantially greater volume of data than wire of comparable size, and optical fiber can accommodate data traveling in both directions simultaneously. To obtain simultaneous two-way communication with wire-guided systems two parallel wires are required.
Riley, U.S. Pat. No. 4,185,796, teaches the use of optical fibers as a communication link between a missile and a remote guidance and control system. The system of Riley discloses two-way transmission of data over an optical fiber which streams from a bobbin in the missile during flight. The specific nature of the missile and its launch system is not disclosed in Riley. Additionally, Riley does not teach a control system providing direct operator input to missile guidance in response to real time target data sensed by the missile.
Fiber optic control systems have been used to provide two-way data transmission in the U.S. Army's Fiber Optic Medium Assault Weapon (FOMAW) and Fiber Optic Guided Missile (FOG-M). While such systems are satisfactory in certain applications, neither FOMAW, FOG-M nor the Riley device are capable of being launched or fired from existing weapons systems such as mortars or cannon. While desirable, an optical fiber guided projectile capable of being fired from a mortar or cannon has not been developed because the exceedingly high "G" loads, in excess of 10,000 G's, generated during firing destroy the relatively fragile optical fiber. Laten et al, U.S. Pat. No. 4,573,647, is directed to a mechanism for deploying optical fiber while relieving the G forces imposed on the fiber during missile launch. That mechanism involves securing the optical fiber on the outside surface of the missile with tape having a tear strip one end of which is secured to the launch vehicle to tear an opening in the tape as the missile leaves the launch vehicle. The Laten et al device, however, has several disadvantages rendering it unable to be used with a mortar or cannon fired projectile. First, by securing the fiber to the outside surface of the missile, the launch tube must have a diameter greater than the missile; the resulting annular space around the missile would permit blow-by in a mortar or cannon reducing the launch thrust. The use of the tear strip would require modification of the mortar tube or cannon barrel in order to attach the end of the tear strip. Moreover, even after the tape is split by the tear strip, the relatively fragile optical fiber would have to pulled through the torn tape during launch.
The subject invention provides an optical fiber guided projectile capable of being fired from an unmodified mortar or cannon. The optical fiber deployment mechanism of the invention does not interfere with the projectile launch performance and precludes damage to the optical fiber during launch. The invention also provides a control system in which direct, real time operator control of projectile flight and target selection is available.
Other objects and advantages of the invention will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalitites and combinations particularly pointed out in the appended claims.